public class Student {
    int student_id;
    String name;
    int age;
    String sex;
    public Student(int student_id, String name, int age, String sex){
        this.student_id = student_id;
        this.name = name;
        this.age = age;
        this.sex = sex;
    }

    @Override
    public String toString() {
        return String.format("学号：%d, 姓名：%s, 年龄：%d, 性别：%s", student_id, name, age, sex);
    }
}
